Lubricants



Patented July 5, 1949 LUBRICANTS Herschel Cantrell,

G. Smith, Wallingford, and Troy L.

Lansdowne, Pa., and John G. Peters,

Audubon, N. J assignors to Gulf Oil Corporation, Pittsburgh, sylvania No Drawing. Application October 23, 1947,

Pa., a corporation of Penn- Serial No. 781,760

- This invention relates to an improved lubricant and particularly to a mineral oil lubricating base blended with an additive which will improve its lubricating properties.

The development of new automotive and other types or power developing machines of increased power output has led to the introduction of beering surfaces which are corroded by oxidation products formed in the lubricant. Also the parts of such power developing machines are corroded and rusted by products formed during use such as water and oxidation products of the lubricant. These difficulties have been overcome to a certain extent by adding substances to the lubricant which reduce the corrosion, rusting and other tendencies.

This invention has for its object to provide an improved lubricant comprising a mineral oil lubricating base uniformly blended with an additive which will retard rust and corrosion when the lubricant is used for the lubrication of power developing machines such as automotive, marine, etc. engines. Another object is to provide an improved mineral oil lubricating base containing an additive which will markedly reduce the corrosion of bearings of a power developing machine. Another object is to provide an improved mineral oil lubricating base having improved oiliness and reduced foaming characteristics. Other objects will appear hereinafter.

These and other objects are accomplished by our invention which includes a compounded lubricant comprising a mineral oil lubricating base uniformly blended with a product obtained by reacting a mixture of sulfurized high molecular weight unsaturated fatty acid and a high molecular weight aliphatic alcohol with maleic acid or maleic anhydride and an olefin oxide or corresponding glycol followed by substantial neutralization with a primary aliphatic amine containing from 8 to 26 carbon atoms. It has been found that sucha compounded lubricant has reduced tendency to rust or corrode the machine parts and at the same time has reduced tendency to foam. It has also been found that the oiliness of the mineral oil base is improved. It is well known that a good lubricant should be capable of adhering to the metal bearing surface under high bearing pressures and such properties is commonly referred to as oiliness.

In the following description we have set forth several of the preferred embodiments of our invention, but it is to be understood that they are 7 Claims. (Cl. 252-34) given for the purpose of illustration and not in limitation thereof.

For convenience in describing the invention we will refer to the use of sperm cil as a source of a mixture of sulfurized high molecular weight unsaturated fatty acid and high molecular weight fatty alcohol. It is to be understood however that suitable mixtures may be obtained from other sources. Thus the sulfurized unsaturated high molelcular weight (1. e. over 8 carbon atoms) fatty acid may be prepared from oleic, geranic, linoleic, erucic etc. acids and the high molecular weight alcohol such as dodecanol, dodecenol, oleylalc etc. may be obtained from any source and added thereto. It is advantageous however to sulfurize an ester of the desired unsaturated acid and alcohol. Examples of other suitable source materials and/or procedure for sulfurization thereof will be found in U. S. Patents 2,179,061 and 2,179,066 to Herschel G. Smith.

The sperm oil used to prepare the improved additive is sulfurized in known manner to incorporate from about 1 to about 12 per cent sulfur to form a neutral sulfurized sperm oil containing the stated amounts of sulfur combined with the sperm oil molecule. Any known method for preparing this product can be used such as, for instance, the method disclosed in the above mentioned U. s. Patent No. 2,179,066 to Herschel G. smith. This sulfurized sperm oil is hydrolyzed to yield a mixture composed mainly of sulfurized carboxylic acids and fatty alcohols of the sperm oil. The hydrolysis may be accomplished in known manner, such as by saponification with an alkali followed by removal of the alkali metal from the soaps by treatment with an acid. or by heating the sulfurized sperm oil in the presence of water and a fat splitting agent such as sulfuric acid.

The mixture thus obtained is reacted with the maleic acid or maleic anhydride preferably after dissolving in a solvent such as a light lubricating oil. The rate of reaction may be increased by heating. The maleic anhydride or maleic acid is advantageously used in equimolecular amounts, based on the sulfurized fatty acid.

The product thus obtained is reacted with an olefin oxide or corresponding glycol such as ethylene, propylene or butylene oxides or ethylene, propylene or butylene glycols. It is necessary that the olefin oxide or corresponding glycol be of low molecular weight, 1. e., less than about eight carbon atoms. The olefin oxide or correspending glycol is preferably added in amounts of 0.25 to 1 mol of oxide or glycol per mol of alcohol contained in the hydrolyzed sulfurized sperm oil. Larger or smaller amounts may be used. The reaction with the olefin oxide or glycol is likewise assisted by heating and is also advantageously carried out in the presence of a solvent. The glycol or oxide is advantageously directly added to the reaction mixture containing the acid anhydride reaction product.

The product thus prepared contains free carboxylic acid and is therefore substantially neutralized with an aliphatic primary amine containing between about 8 to 26 carbon atoms. Normal straight chain primary amines such as decylamine and octadecyl amine are advantageously used but it is satisfactory to use unsaturated primary aliphatic amines such as undecenyl amine. Mixtures of straight chain primary alkyl amines such as cocoamine are advantageous because of their relative cheapness. Cocoamine is a commercial mixture of higher alkyl amines prepared from eocoanut oil fatty'acids. It contains a major amount of primary dodecyl amine and typical samples thereof have been foundto have an average molecular weight ranging from 200 to 210. The amine is used in an amount such that the reaction products will be substantially neutralized.

The final product can be directly incorporated in the mineral oil lubricating base preferably in amounts of about 0.1 to per cent on a solvent free basis. However larger or smaller amounts may be used to obtain reduction in corrosion, rusting and foaming properties. It is advantageous to prepare a concentrate of this product in a mineral oil or fraction thereof and use this concentrate as a convenient vehicle for incorporating in the lubricating base.

Example I.Into an iron reaction vessel were charged 411 pounds of 45 winter sperm oil and 30 pounds of powdered sulfur. The temperature was increased to 350 F. and held at that temperature for two hours. Then 700 pounds of a light lubricating oil was added, followed by 72 pounds of 50 per cent'caustic soda solution, and reaction at 320 F. and 30 pounds pressure for five hours. The mixture was cooled to 120 F., and 135 pounds of per cent sulfuric acid was added. The temperature was raised to 175 F. and held at that temperature for two hours.

The mixture was allowed to settle and. the aqueous layer drawn off. This material was then washed three times with 30 gallons of water per wash.

The washed material was dried at 240 F. under 15 in. mercury pressure.

The dried material was treated with 40 pounds of maleic anhydride at 240 F. for one hour. The reaction product was cooled to 120 F., and 24 pounds of propylene oxide was added under a reflux over a period of two hours. The temperature was then raised to 180 F., and 200 pounds of cocoamine was added to neutralize the resulting acidity.

The finished product had the following properties:

Gravity: API 25.3 Viscosity, SUV: 210 F 78.3 Pour: "F +50 pH value 7.6 Neutralization No 22.0

Example II.--The product was prepared according to Example I, except that the sperm oil 4 was treated with only 1 per cent by weight of sulfur in the first step. The product had the following properties:

Gravity: API 28.0 Viscosity, SUV: 210 F 58.2 Pour: F +50 pH value 7.7 Neutralization No 18.7

Example 111.-Another example of this compound was prepared by treating the sperm oil with 12 per cent by weight of free sulfur in the first step. The product had the following properties:

Gravity: API 20.1 Viscosity, SUV: 210 F 192.2 Pour: F +50 pI-Ivalue 7.6 Neutralization No 16.0

Example IV.-A product was prepared by a method similar to that described in Example 1, except that one mol of propylene oxide was used. The product had the following properties:

Gravity: API 26.0 Viscosity, SUV: 210 F 74.8 Pour: F +50 pH value 7.3 Neutralization No 19.4

Example V.A refined turbine oil was treated with 0.25 per cent (on a solvent free basis) of an inhibitor prepared according to Example 1. Comparison of the base oil and inhibited oil is as follows:

Base 011 gfi Gravity: API 27. 2 27.1 Viscosity, SUV:

F 296 294 210 F 50. 0 49.9 Flash, 0C: F. 390 390 Fire, OC: F 445 445 Pour: F -15 15 Color, NPA. 5.0 5. 0 Carbon Residue: Per Cent 0.11 0.11 Neutralization N o 0.02 0. 02 Corrosion Test:

ASIM D66546T- Steel Rod: Appearance rust bright Area Rusted: Per Cent 100 0 Air Bubbling Foam Test:

Method 435, Gult Vol. Oil 82 Foam: Vol. Oil 77 F" 4. 5 1.02

Example VI.-A lubricating oil was treated with 0.25 per cent (on a solvent free basis) of an additive prepared according to Example II. Comparison of the base oil and improved oil is as follows:

Example VII.-'A lubricating oil was treated with 0.25 per cent (on a solvent free basis) of an additive prepared according to Example III.

The compounded lubricant of the present invention has many advantages. It will be noted that the corrosion and rusting of metal surfaces is greatly reduced so that the moving parts of power generating equipment would remain in good condition for a longer period and would continue to deliver approximately the original power output after many hours of use. The compounded lubricants of the present invention also have increased oiliness so that they can be used to effectively lubricate bearings which are operating under high pressures. These products also have greatly reduced foaming characteristics. This is, of course, important since a lubricant which foams to a large extent cannot be used to lubricate engines operating under extreme conditions. These advantages are not obtained if an acid or anhydride other than maleic is used.

What we claim is:

1. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with a small amount, suflicient to retard rust and corrosion, of a product obtained by reacting a mixture of sulfurized unsaturated fatty acid containing over 8 carbon atoms and an aliphatic alcohol containing over 8 carbon atoms with a member of the group consisting of maleic acid and maleic anhydride, then reacting the product thus produced with a member of the group consisting of olefin oxides containing less than about.

8 carbon atoms and glycols corresponding thereto, both of said reactions being carried out at a temperature between about room temperature and about 240 F. and then neutralizing the re-. action product with an aliphatic primary amine containing between about 8 and 26 carbon atoms.

2. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with 0.1 to per cent by weight of a product obtained by reacting a mixture of sulfurized unsaturated fatty acid containing over 8 carbon atoms and an aliphatic alcohol containing over 8 carbon atoms with a member of the group consisting of maleic acid and maleic anhydride, then reacting the product thus produced with a member of the group consisting of olefin oxides containing less than about 8 carbon atoms and glycols corresponding thereto, both of said reactions being carried out at a temperature between about room temperature and about 240 F. and then neutralizing the reaction product with an aliphatic primary amine containing between about 8 and 26 carbon atoms.

3. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with a small amount, sufiicient to retard rust and corrosion, of a product obtained by reacting a mixture of sulfurized unsaturated fatty acid containing over 8 carbon atoms and an aliphatic alcohols containing over 8 carbon atoms with a member of the group consisting of maleic acid and maleic anhydride, then reacting the product thus produced with an olefin oxide containing less than about 8 carbon atoms, both of said reactions being carried out at a temperature between about room temperature and about 240 F. and then neutralizing the reaction product with an aliphatic primary amine containing between about 8 and 26 carbon atoms.

4. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with a small amount, sufiicient to retard rust and corrosion, of a product obtained by reacting hydrolyzed, sulfurized sperm oil with a member of the group consisting of maleic acid and maleic anhydride, then reacting the product thus produced with a member of the group consisting of olefin oxides containing less than about 8 carbon atoms and glycols corresponding thereto, both of said reactions being carried out at a temperature between about room temperature and 240 F. and then neutralizing the reaction product with an aliphatic primary amine containing between about 8 and 26 carbon atoms.

5. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with a small amount, sufficient to retard rust and corrosion, of a product obtained by reacting hydrolyzed, sulfurized sperm oil with maleic anhydride, then reacting the product thus produced With propylene oxide, both of said reactions being carried out at a temperature between about room temperature and about 240 F. and then neutralizing the reaction product with an aliphatic primary amine containing between about 8 and 26 carbon atoms.

6. As an'improved compound lubricant, a uniform blend of a mineral oil lubricating base with a small amount, sufiicient to retard rust and corrosion, of a product obtained by reacting hydrolyzed, sulfurized sperm oil with maleic anhydride and then reacting the product thus produced with propylene oxide, both of said reactions being carried out at a temperature between about room temperature and about 240 F'. and then neutralizing the reaction product with cocoamine.

7. As an improved compound lubricant, a uniform blend of a mineral oil lubricating base with .1 to 5 per cent by weight of a product obtained by reacting hydrolyzed, sulfurized sperm oil with maleic anhydride, then reacting the product thus produced with an olefin oxide containing less than about 8 carbon atoms in amounts of between 0.25 and 1 mol per mol of alcohol present in the hydrolyzed, sulfurized sperm oil, both of said reactions belng carried out at a temperature between about room temperature and-about 240 F. and then neutralizing the reaction product with cocoamine.

HERSCHEL G. SMITH. TROY L. CANTRELL. JOHN G. PETERS.

No references cited. 

